In its January Volume, the Institute of Food Technologist featured an in-depth article titled Coffee Quality Testing. After explaining the coffee basics, the author relies on the expertize of our own Spencer Turer to explain how and why coffee is tested:
Evaluating Quality
The quality of the coffee consumers drink depends on numerous factors, such as the cultivar, growing altitude, climate, soil chemistry, harvesting and processing conditions, drying method, storage conditions (temperature, humidity), transportation method (container type and size), roasting conditions, grind size, packaging, age, and brewing method. Spencer Turer, Director of Coffee Operations at the independent coffee-testing company Coffee Analysts (www.coffeeanalysts.com), said that testing is conducted throughout the supply chain, but the amount of testing changes. Exporters and importers usually use basic sensory and physical evaluations to determine whether the product meets their quality standards for grade and are free of sensory defects. At the roaster, the testing becomes a lot more rigorous, and the regional, national, and multinational coffee companies become much more involved in dynamic quality control, using a variety of instrumental analyses as well as sensory evaluation. Turer said that although many strides have been made in instrumentation for flavor and aroma detection and identification, the simplest, least expensive, and most replicable results in coffee testing are obtained by sensory analysis, specifically the cupping method for flavor and aroma.
In this method, which is used at all stages of production, the taster or “cupper” first evaluates the overall visual quality of the beans (grading the beans for defects, size, moisture, aroma, and color), then roasts a sample in a laboratory roaster, grinds the roasted beans, and evaluates the roasted coffee fragrance. The cupper then adds boiling water to a standard amount of the ground coffee and allows the coffee to steep in the cup for about four minutes, smells the aroma, breaks the crust of grounds to complete the aroma evaluation, and then skims the floating grounds and oils from the top of the cup. After allowing the coffee to cool, the cupper tastes the beverage by forcefully slurping a spoonful to see if it meets expected standards, and then spits it out.
Using this procedure, the cupper can evaluate the coffee sample quality and blend different beans for product development or to determine the proper roast for specific flavor characteristics. According to the NCA, an expert cupper can taste hundreds of samples of coffee a day and still taste the subtle differences between them. Turer pointed out that the cupping process follows scientific protocols to ensure that the only variable in the test is the coffee being sampled. All aspects of the process are strictly controlled, including coffee roast parameter, time between roasting and cupping, grind size, coffee portion weight, water quality, water temperature, cupping vessels, and so on. The cupper records the intensity and quality of the dry bean fragrance and the aroma, acidity, body, flavor, and finish of the beverage.
Turer said that the physical laboratory tests that may be conducted on green coffee are density, moisture content and water activity, bean size, grade (defect counts), and color. Tests for roasted coffee are residual oxygen and carbon dioxide within packages, moisture content and water activity, roast color, grind particle size or broken bean counts, brewed coffee dissolved solids, pH, and Brix/refractive index. Chemical testing for coffee includes ochratoxin A, caffeine, nutrient analysis, microbiological analysis, and pesticides. Other tests that may be performed on roasted coffee are caffeine, chlorogenic acids, lipids, carbohydrates, total polyphenols, total proteins, and mycotoxins. Standard analytical methods for coffee have been published by AOAC International (see table), the International Organization for Standardization (ISO), and other organizations.
Spencer Turer from Coffee Analysts attended Let’s Talk Coffee 2011 in Salinitas, El Salvador along with Jeff Alpert and Jenny Perez from Coffee Extracts & Ingredients. The conference is organized by Sustainable Harvest and attended by over 375 attendees from 24 different countries. The theme for this years conference was “Redesigning the Coffee Supply Chain.” Spencer participated in meetings with coffee producers and roasters regarding coffee quality and harvest expectations.
During the conference the region experienced torrential rains that caused extreme flooding and mudslides. However the poor weather did not dampen our spirit for building strong supply relationships and discussing coffee quality for calibrations amongst supply chain partners.
Preparing for a cupping
Coffee Extracts' Jeff Alpert (second from left) at one of the talks
Let's Talk Coffee: a great opportunity to hear what's happening in the industry
When it comes to coffee (or any other food product, for that matter), spider graphs—AKA spider charts or radar charts or star charts—are incredibly useful for documenting sensory attributes for both flavor and aroma. These charts can be a useful tool to visually compare and contrast samples or as a point of reference to benchmark for product development or specification creation.—i.e. “I want my coffee to taste like THIS.”
What Is A Spider Graph?
In essence, a spider graph displays a series of attributes on a predefined scale to create a visual representation of how a product tastes.
Spider Graph Example
How are Spider Graphs Created?
The key to spider graphs is in blind testing by a trained panel. At Coffee Analysts, a team of professional cuppers (tasters) convene in a dedicated sensory laboratory devoid of external stimuli: no talking, no perfumes, no distractions. These cuppers independently analyze the coffee in terms of taste and aroma as described by the SCAA Flavor Wheel (see below). They cup the coffee at least three times, individually record their test results for each attributes intensity and quality, and then discuss their findings. Led by the Director of Coffee Operations the sensory panel, as a group, agree on 10-15 most prevalent attributes and chart the results.
SCAA Flavor Wheel
Why Are Spider Graphs Useful?
Coffee Analysts’ clients often use spider graphs to map roasted coffee sensory changed over time in order to determine consistency. As an example, a private label retailer has seen sales flatline for its best seller, “Acme Breakfast Blend.” The company suspects a recent change from one of its suppliers has adversely affected taste. If Acme had a spider graph of the original, best-selling “Breakfast Blend,” the company can use it to analyze the poor-performing coffee (see example below). Coffee Analysts can show how (or if) the flavor profile has changed significantly, and then make recommendations on how to improve.
Example – click on image to enlarge, use > and < keys to advance / go back:
Acme Blend Original
New blend - notice different flavor profile
Spider Graphs are an important tool for quality control programs and product development projects. The visual representation of various attributes can be an easy to read and understand profile of coffee character.
Making consistently good coffee is all about setting high standards. The best way to do this is to test your coffee regularly to make sure it meets those standards. But where do you start?
Coffee Analysts now offers bundled coffee testing packages for green coffee and roasted coffee. These testing packages give you a comprehensive report of what’s happening with your coffee, from staling risks to taints to cupping scores.
Whether you’re a small roaster or a nation-wide retailer, there’s a testing package that can help you ensure the quality of your coffee.
Best of all, all coffee testing packages include Sensorial Analysis and a comprehensive report.
Prices vary depending on volume, quantity and your goals, so contact us for a quote.
The Agtron might sound like an agricultural superhero robot, but behind its name lies a simple coffee test: consistency.
The Agtron uses near infrared light to analyze the color of ground or whole bean coffee. It then outputs an easy-to-read number that represents the degree of roast. The lower the number, the darker the roast. For example, espresso roasts often have an Agtron reading in the 20s, dark roasts lie in the 30s, regular roasts between 40-55, and light roasts anywhere above 55.
Coffee Analysts uses the Agtron to determine roast consistency. We perform three Agtron readings for each sample to make sure they all fall within a certain range that’s determined by the customer. We then report all our findings back to our customers so they can adjust their roasting processes accordingly.
It’s all about consistency within a bag, and consistency from roast to roast. And the Agtron is the best tool to do test for coffee roast consistency.
While we can tell you anything and everything there is to know about coffee, when it comes to actually growing coffee from seed … well … we’re not exactly green thumbs. The problem is that we love having coffee plants around the office.
Thank goodness for University of Vermont Adjunct Faculty Lecturer Colleen Armstrong.
Armstrong gets our seeds going in the greenhouse so we have some foliage around the coffee lab. Without her, we’d be SOL.
Just don’t expect us to start brewing any of the office coffee plant bounty: a coffee plant needs as much as four years to bear fruit, and it takes 2000 cherries to make one pound of coffee.
At the Coffee Analysts Coffee Laboratory, we use a range of technical equipment to analyze the physical characteristics of green and roasted coffee. For all our coffee testing packages, we perform many tests, but there are few things in particular that we look for.
Comprehensive coffee testing will help you understand how to source, roast and brew consistently great coffee. However, testing one sample one time will not reflect the state of your overall coffee program; it will only provide a snapshot of the particular sample.
While some specialty roasters test every batch they produce, it often is unreasonable for a roaster to go to extreme lengths to ensure quality. In our opinion, the key is to figure out a level of testing that can account for the variability of your coffee without blowing budgets and time constraints.
When coffee is brewed correctly, there is truly nothing like it. You do a double-take, look incredulously at the cup in your hand and say, “man … that’s GOOD.”
But in order for the coffee to come out just right, the correct brew parameters must be in place: water quality, water-to-coffee ratio, water temperature, and grind. When brewed correctly, the coffee’s best flavors are released quickly, and bitterness will be present, but it will be perceived as more of an aftertaste or “finish.” Cutting off the extraction at a certain point can control the amount of bitterness.
The value of green coffee is in its flavor and how it can be used. Some green coffees are quite valuable and have a long-standing reputation of high quality (Kenyan, Kona, Guatemalan Antigua, Jamaican Blue Mountain), others are not always deserved.
Those that can be sold as a single origin command the highest prices. Next in line are lesser-known origins, some of which are every bit as good as the “stars,” but do not have a reputation in the marketplace. The “blenders” are coffees that may be all right on their own, but are usually blended with other components.
When Coffee Analysts tests green coffee, we conduct a physical and a sensory analysis, and then provide our clients with a detailed report. From this report, our clients can adjust their blends, roasting methodology, etc. to achieve the best flavor profile.
When testing coffee, the roast degree will determine what flavor component of the individual coffee is emphasized and is a primary determinant of the flavor profile.
More acidic coffees may maintain their acidity better at lighter roasts, while those that naturally have heavier body may be able to maintain that body through darker roasts. Some origin flavors can be more clearly perceived when the roast is lighter (more acidic), while some are obscured at the same level of roast.
Any coffee, no matter of what quality, can be affected dramatically at the stage of brewing. Brewing is a chemical reaction between hot water and coffee. According to work done by the Coffee Brewing Center, while roasted ground coffee is about 30% soluble by weight, only 18-22% of that soluble material results in desirable coffee flavor. This material must be present in a certain concentration to be best appreciated. For more details on ideal conditions for producing a satisfying cup, see the SCAA website.
Packaging and the maintenance of packaging equipment is one of the biggest challenges in the roasting facility. Coffee Analysts has designed shelf–life tests so that several samples from a batch are tested at once. Especially in the case of coffee packaging, only testing one bag will not give adequate information about the packaging system.
Use of the leak detector: When excessive oxygen is found, it is important to determine the source. If the equipment is not sealing the bag properly, pinhole leaks can develop that allow small amounts of oxygen into the package over time (immediately after manufacture, no oxygen will be detected). By isolating the location of these leaks, the equipment can be adjusted as necessary.
Freshness is a major determinant of roasted coffee quality and consumer satisfaction. The rate of coffee staling will depend upon the amount of contact with oxygen. Conditions of heat and added moisture will accelerate staling. Moisture-resistant sealed packaging with a minimum of oxygen content is the key to coffee shelf life.
The training focused on “Tongues & Noses” with emphasis on tasting coffees from around the world. Jacqui worked with the CA staff on identification of faults, taints and positive attributes, and departed with a “taste bud high,” ready to get back into her lab.
The Orlando Sentinel recently blogged that First Watch, a breakfast, brunch and lunch chain based in Bradenton, Fla., is now selling its Sunrise Select Premium Blend ground coffee at all 82 locations.
Our coffee product development team helped First Watch develop this special blend. According to a First Watch press release:
First Watch customers can pick up a 12-ounce bag of Sunrise Select™ ground coffee for only $5.99 plus tax. Sunrise Select is a proprietary blend of high-grown Panamanian, Mexican and Columbian coffee beans that is slow-roasted to create a unique, rich and delicate flavor. It was developed in partnership with highly-regarded coffee expert Coffee Analysts and is roasted and distributed by First Watch’s vendor-partner Royal Cup Coffee.
The value of green coffee is in its flavor and how it can be used. Some green coffees are quite valuable and have a long-standing reputation of high quality (Kenyan, Kona, Guatemalan Antigua, Jamaican Blue Mountain), others are not always deserved.
When 
